Its a bit unfair imo.
Uncharted 1 = People thought it was another Tomb Raider game.
L4D1 = People hyped it up because it looked like a fun and great horror co-op game.
Uncharted 2 = People was taken by surprise with U1 and found the best story ever in a videogame.
L4D2 = People got dissapointed with the lack of support, no story and it got repetetive.
By those standards, Uncharted 2 is bound to win. Though the 360 always have a strong holiday and a greater userbase that tend to like those kinds of games. Which might give Uncharted 2 a run for its money.